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A092831
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Indices of prime Motzkin numbers.
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2
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OFFSET
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1,1
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COMMENTS
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Next term (if it exists) > 2*10^7.
This sequence may be finite, for the reason that with increasing n, the density of trivially composite Motzkin numbers approaches 1. For 7*10^6 < n < 20*10^6, all Motzkin numbers have a small factor not exceeding 63809. See below.
Rowland and Yassawi, and later Burns, established asymptotic densities of A001006(n) modulo primes up to 29. In particular, the asymptotic densities of A001006(n) == 0 modulo 3, 7, 17 or 19 are 1. (End)
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LINKS
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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